The present paper expounds on the effect of a near-surface cavity, when the solid surface is subjected to the Coulomb frictional loading of an asperity moving at moderately high speed. The medium under consideration is represented by a solid half-space which is coaled with a thin layer of solid wear coating. The cavity is assumed to be rectangular in cross section. The temperature field and its gradient in the vicinity of the cavity are obtained during the traverse of the asperity over the surface near the cavity. The cavity defect results in a material nonuniformity mathematically modelled in term of the material coordinates. The resulting governing differential equation is time-explicit and transient. A general finite difference formulation is developed, from which numerical solutions are obtained for problem with a cavity at various positions relative to the surface-layer/substrate interface. Because of the poor heat transfer characteristics of tile cavity, the temperatures in the surface layer above it are higher than those in the surrounding region. This phenomenon causes a higher temperature gradient, especially at the trailing corner of the rectangular cavity. There, the direction of the maximum temperature gradient is at a significant oblique angle to the wear surface. The combined effect of a higher temperature gradient and an oblique direction would result in a much larger shear stress in the surface-layer/substrate interface. This phenomenon could lead toward delamination of the coating near the cavity.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Tribology Conference in Pittsburgh, Pennsylvania, October 20–22, 1986